Electrocardiographic mapping (ECM) is a technology that is used to determine and display heart electrical information from sensed electrical signals. Mapping of cardiac electrical activity becomes further complicated in the presence of certain types of arrhythmia such as fibrillation, including atrial and ventricular fibrillation. The cardiac signal contains several consecutive depolarizations of the tissue. Most methods in practice today that describe analysis of cardiac depolarization or activation rely on a priori knowledge of periodicity or cycle length of the signal (e.g., for 3D activation mapping). In cardiac activations where there is no specific periodicity or cycle length, analysis techniques such as phase mapping have been developed. However, existing phase mapping approaches are invasive, such as including a basket catheter(s) inserted into the heart or injecting dye into the heart muscle and performing optical imaging. Optical imaging dyes are toxic in humans, and the resolution provided by basket catheters is not sufficient to generate an accurate phase map of human atria.